Well, yes, I agree with you completely. Thats why I like to look at QB rating AND the ESPN QBR AND FootballOutsiders and PFFs ratings because those look more at situations like that and competition etc. and the general average of all those gives you a sense of where a QB really is.
And in Goffs case in 2020 that was about 21st in the league among starting QBs. Not good enough at all. But again I also think it is OK to say he was better in the postseason.
I think the Rams main issue vs GB far and away was the run defense and inability to make stops and get the ball back in any sort of decent position.